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Wellington Harbour

Te Whanganui-a-Tara / Wellington Harbour is a deep, largely subtidal estuary. Average harbour depth is between 10 and 30 metres, so it acts as a natural settling area and has a largely muddy bed. Tidal action largely determines water circulation and the harbour is relatively well flushed by clean seawater on each tide. 

Greater Wellington began environmental monitoring in subtidal areas in 2006, with further surveys completed approximately every four years.


The majority of the natural stream estuaries that flow into to the harbour have been piped and modified. Only the larger estuaries located at the mouth of Te Awa Kairangi / Hutt River, Korokoro Stream and Kaiwharawhara Stream remain as significant open waterways, although these are also heavily modified.  

The harbour has lost much of its previously extensive dunes, saltmarshes and tidal flats. Approximately half of the harbour margin has been modified by stone seawalls flanking road and rail corridors and the Kaiwharawhara and Seaview port areas. The scarcity of remaining habitats places a high level of importance on maintaining and enhancing their ecological values.  

Wellington Harbour is busy recreational area, with active shipping ports.  

Threats to the ecological health of Wellington’s estuaries include climate change, stormwater discharges, wastewater overflows and coastal development. 

Estuary summary

What makes my estuary unique?

Explore the characteristics of this estuary


Estuary characteristics

  • Tide
    Tidal influence
  • Flushing time
  • Key rivers
    • Kaiwharawhara Stream
    • Korokoro Stream
    • Waiwhetū Stream
    • Hutt River

What's happening upstream?

See results from monitored river quality sites influencing this estuary

River quality

What's happening upstream?

The physical characteristics and health of estuaries are influenced by the rivers and streams flowing into them. For instance, when it rains the mud and contaminants generated on land can be washed into rivers and eventually flow into the estuary. The health of our rivers and streams can therefore be very important for Estuary Health, and understanding the upstream pressures can help with interpreting estuary monitoring data.

Monitoring is undertaken for a range of river health indicators (e.g., water quality and ecology) in many catchments across the region. Where there are monitored river catchments that influence this estuary, these are shown below. You can click through to view monitoring results from these River Quality sites to see current state and how health has changed over time.

What surrounds my estuary?

See land cover information from monitored catchments that surround this estuary

Land cover

What surrounds my estuary?

The physical characteristics and health of estuaries are influenced by local geography and the way we use our land. This is because estuaries are the receiving environments for many of our land use activities. Land cover information can be used as an indicator of land use, therefore knowing the surrounding land cover can help us understand which pressures might be affecting Estuary Health.

Where there is land cover information available for nearby catchments, these are listed below. These figures show the types of vegetation and built or natural features that surround the estuary margins and the rivers that flow into this estuary. You can click through to the Land Cover topic to see these land cover classes broken down into further detail, and view changes over time.

Monitored sites 15

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